Authentication is a process of confirming an identity of a person or thing. Authentication has applications in computing, information, manufacturing, packaging, human physical access, and consumer products. Authentication varies in its effectiveness. On one end of a spectrum, some forms of authentication can ensure absolute or near-absolute authenticity. On another end of the spectrum, some forms of authentication can ensure less than absolute authenticity or an acceptable level of authenticity. The tradeoff between the two ends of the spectrum may depend on complexity, ease of use, and cost.